Vapor-liquid cooling cycle for engines



M. F. KNoY 2,413,770

VAPOR-LIQUID COOLING CYCLE FOR ENGINES v*1mm Jan. 24, 1944 Y R Q Jan. 7, 1947.

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Il '.U-U.. ...n.f' I' l Il INvfN-roe .6 MAQ/0N E KNOY Haul.; K/scfg Fans? Haze/s Patented Jan. 7, 1947 TED TTS PAENV f enano VAPOR-LIQUm COOLING @VELE FR ENGDIES Marion 3W. Knoy, Long Beach, Calif., assigner to A Robert T. Collier, Willmington,@aliia Applicaties January 24, 1944, senat No. 5119,44?

2l Claims. (Cl. 12S-17d) This invention relates to the dissipation of heat for cooling internal combustion engines and the like, including gas turbines.

The principal object o'f the invention is to efpressure of the closed system automatically conf trois the temperature, of the motor, atmospheric pressure conditions having no eilect in the sealed circuit.

Other objects of the invention are to eliminate the freezing hazard in automobile engine cooling, to eliminate the necessity for a liquid circulating pump between the motor jacket and the radiator, and to avoid -the necessity of frequent replenishment of motor cooling liquid as is now common. l

Other objects and advantages will appear from the following disclosure.

Briefly stated, the invention resides in employing a closed or hermetically sealed cooling system wherein there is permanently contained a cooling liq'uid of appropriate boiling point. According to a preferred form of the invention, the liquid is a mixture having a constant boiling temperature, and, according to a further preference, one element of the mixture is water. Usually the boiling point of the mixture is below the boiling point of water, whereby to establish the` boiling point at the most eilcient temperature for operation of a given engine, for example, at around 180 F., but it may approximate the boiling point of water for some uses.

Another phase of the invention resides in the employment of a sealed vapor condenser at an elevation above the motor, whereby the condensate from the vapor of the cooling liquid returns to the motor by gravity feed. This condenser may conveniently conform in general with the modern type of automobile radiator so long as the condensing* portion is located at said elevated position so as to return the condensate to the motor.

In the accompanying drawing, there is illustrated diagrammatically one embodiment of a system in which the presentinvention is practiced.

In the drawing, I show a hood' 5 of an automobile having a dashboard 5 at the rear of the hood, together with a cowl 1, a windshield 8 thereabove, and an instrument panel 9. Under the hood 5 there is shown a conventional internal combustion engine E having an engine block Il) which is connected with a condenser C located in a cooling position under the forward end of the hood, andy with a second condenser K 'behind the dashboard 6 where it may heat the drivers compartment, these parts constituting the principal units of the system.

The engine block ill has the usual cylinder bores ll in whichl pistons l2 are reciprocated by means of connecting rods E3 having bearings id conventionally mounted upon a crank shaft l5 for propelling the automobile in the usual manner. The engine block carries a unit manifold I6 for supplying fuel to the engine and removing exhaust gas, as is common in a typical in= terna] combustion engine. Also provided is a head I'l,'constructed somewhat after the fashion of a conventional engine head, secured to the engine block it in any known or preferred manner, and sealed in relation thereto by means of a conventional 4gasket i8.

'Ihe engine block il! is provided with a series of water passages i9 constituting a cooling jacket receiving the cooling liquid, as/is well known in the art, which passages I 9 extend vertically in the'block and communicate with passages 2d in the head il, the passages 2@ in turn leading to a chamber 2l in said head Il. The head ll is of such proportions and,construction that the chamber 2l provides for the maintenance of a liquid level at an intermediate point with a vapor space thereabove. A cooling liquid, such as that hereinafter described, is supplied to passages i9 by means of a liquid supply line 22 which communicates with the bottom of the passages i9 as shown. A

Since cooling of the engine during operation is eiected by vaporization of the cooling liquid, after the engine has warmed upin operation quantities of the liquid vaporize in the passages I9 and the vapors rise through the liquid to the surface thereof in the chamber 2l where they separate and accumulate in the top of the chamber 2| passing thence by way of a neck 24 into a vapor line 25 which leads to a`vapor receiving space 26 in the topof the condenser unit C. The

intermediate portion of the condenser C below the vapor ,receiving space 26 constitutes a condenser section 2'l comprising coils or tubes wherein vapors passing downwardly from the receiving space 26 are condensed into liquid. The condensate accumulates by gravity in a liquid receiver 28 constituting the lower portion of the condenser C. As liquid is vaporized in the engine block I0, liquid condensate flows by gravity from the liquid receiver 28 to the supply line 22 bile radiator. A The condensing section 21 is high f enough so that liquid condensed therein will flow back to the engine by gravity, and its structure may be of any suitable design, such as the common cellular construction or one of the common tubular constructions provided with nns as shown, or hairpin coils provided with ns. When desirable to regulate the cooling in the condenser C, adjustable louvers 30 are preferably positioned in front of the condenser C, the louvers being subject either to manual or thermostatic control as may be deemed suitable, although it will be understood that such louvers are not essential in view of the fact that the operation of the system is largely automatic and that such louvers merely provide a closer temperature control. As shown. the louvers 30 are pivoted in a louver housing 3| on the front of condenser C, and a thermostatic control is illustrated where a thermostat 32 inset in the receiver 28 actuates a bell crank 33 which in turn actuates a louver-adjusting rod 34 connected with the louvers 30.

Inasmuch as there is a very considerable amount of heat that is taken from .the engine i and commonly Wasted to the atmosphere through the condenser section 21 of the condenser C, it may be desired at times to take advantage of some or all of this heat for heating the passenger space or drivers compartment in the automobile body.v This may be conveniently accomplished by providing a branch line 25a leading from the neck 24 on the cylinder head l1 to 'carry some or all of the vapors therefrom into the second condenser K which may be suitably mounted ,within the car body, for example, on therear of the dashboard 6 as shown. This condenser K is a substantial duplicate o! the condenser C, having an upper vapor receiving space 26a, a condenser section 21a, a liquid receivingl chamber 28a, and

a liquid return line `22a leading to the bottom of the engine block l0 to communicate with the passages I9. The condenser K may be cut in or out of the system by a valve 35 -mounted in the line 25a and actuated through the medium of a housed cable 36 which is connected at one end with an arm 31 operating the valve 35 and has its other end mounted in the instrument panel 9 whereit is provided with a control 38 located in the drivers compartment for convenient manipulation. When condenser K is made operative by opening valve 35, the'system constitutes both a cooling device for the engine and a heating device for compartments in the car.

The heating effects of the condenser K may be regulated by controlling passage of air through the condenser section Ila. This is accomplished in the form shown by providing an opening 39 in the dashboard 6 in front of the condenser section 21a and placing adjustable louvers 40 immediately behind the section 21a in a louver housing 4i" in which they are pivoted.l The louvers 40 may be adjusted as desired, for example, by means of a thermostatic control 42 mounted on the instrument panel 8 and responsive to temperature in the drivers compartment. The thermostat 42 operates a pivoted bell crank 44 actuating a link 45 connected to a second pivoted` bell crank45 which in turn operates a louveradjusting rod 48 connected with each louver 40. An electric fan 50 and its driving motor 5l are vshown positioned in front of the opening 39 f of its normally operative relation, this being done through the medi-um of a valve 60 in line 25 corresponding with valve 35 in line 25a, and operable by a housed cable 6I connected at onel end with an arm 62 actuating valve 50. The other end of cable 5l extends through the dashboard B and is mounted in the panel 9 for operation by a control 55 which may be manually actuated as required.

The operation of the present sealed cooling system involves primarily vaporizationof a constantv boilingliquid inI the passages I" of tlu` engine block i0, whereby the engine is cooled due to the heat consumed in the vaporization of the liquid. The resultant vapor separates from the liquid in the chamber 2l at the liquid level indicated, rises through the neck 24, 'and passes through either or both ofthe lcondensers C and K, being received in the vapor spaces 28 and 26a respectively thereof, then passing down through the cooling tubes of condensing sections 2l andl 21a respectively, the condensate collecting in the respective receivers 28 and 28a, whence the con densate returns by gravity through the lines 22 and 22a to the passages ISinthe engine block il! to effect further evaporative cooling.

The indicated passage of the vapors selectively through either or both of the condensers C and K is effected by suitable operation of the valves 35 and'60. If the drivers compartment becomes too warm when the condenser K is operating. the louvers 40 will close or partly close and stop Aor reduce air passage through opening 39 and condensing section 21a. At such a time valve 60 will have been opened by the control 65.

lIf the temperature in the engine becomes too high, excess vapors are generated, thereby increasing the pressure in the system and raising the temperature of the resultant condensate in receiver 28. This temperature rise affects the thermostat 32 in the receiver 28, thereby causing actuation of the adjusting parts 33 and 34 to open or partly open the louvers 30, as a result of which more cooling air passes through the condensing section 21, thereby condensing the vapors more rapidly, and lowering the pressure in the system, which in turn results in lowering the temperture of the condensate in the receiver 28. Preferably, thermostat 32 is disposed inthe upper portion of the body of condensate in receiver 28 so that it always responds to the temperature of the condensate mostrecently formed.

It will be noted thatkwith this type of cooling, there is no circulation of liquid as such. Rather, the agent that is circulated is the vapor formed in connection with the coolingof the engine.

Since the system is sealed and the vapor is continuously generated during engine operation and rises from the surfaceof the liquid in the chamber 2i at a rate varying with the amount of heat produced by the engine. the condensation of the vapor and the return of the resultant condensate to the engine yield an automatic regulation which insures a substantially uniform engine temperature.

As to the liquid to be employed, there are several liquid mixtures having constant boiling points within a range which is suitable for-the present method of cooling internal combustion engines. taining water as one constituent and an alcohol, ketone, ester, or similar organic substance as another constituent. As preferred liquids, the following may be employed according to the boiling pointdesired. Ethyl alcohol and water from a suitable mixture when containing 95.6% by weight of the alcohol and 4.4% by weight ofwater. This mixture has a constant boiling point of 78.15 C., or about 173 F. Thus, where it is desired to operate an internal combustion engine at a temperature approximating the average now commonly used, this ethyl alcohol mixture may be used. However, in many instances it will be preferable to use higher engine temperatures than have heretofore been commonly employed. Thus, for such a use there is a constant boiling mixture of secondary butyl alcohol and Water which contains 72.7% of the alcohol` and 27.3% of water, which mixtureboils at 189.5"

F. or 87.5 C. Again, in some engines a mixture having a boiling point approximating that of water may be more desirable, and such a constant boiling point mixture comprises 12.7% cli-acetone alcohol and 87.3% water, this mixture boiling at 210 F. or 98.8 C. These figures may vary slightly from the actual according to different authorities but they satisfy practical purposes. As described hereinafter, under conditions of. operation in my system the boiling point' of the mixture may rise due to increases in pressure in the system. r

The use ofthe constant boiling point liquid mixtures above indicated will at the same time eliminate the freezing hazard experienced when Water is used, because these mixtures constitute good anti-freeze mixtures. Of course, it might be possible to use different mixtures of alcohols and water, and other kindred mixtures, as has often been done heretofore in preparing anti-l freeze solutions. However, unless the exact percentages to constitute constant boiling temperature mixtures are employed, there is unequal distillation in the engine and the result is that the boiling point is changing constantly during use and there is no close temperature regulation.

Therefore it is highly preferable to use constant,

boiling temperature mixtures such as those given above or any others having a desired boiling point.

Water is one of the most eifective evaporative coolers and has the highest latent heat of vaporization among the ordinary liquids, but in a closed system of the present invention its boiling point may be too high in many instances, and, of course, it presents a freezing hazard because of its high freezing point. f the liquids to be used with water which are suitable for this purpose and impart a sufficiently'low freezing point, while at the same time making suitable constant boiling mixtures with water, ethyl alcohol is very desirable because it has .the highest latent heat of vaporization, and at the same time is chemically stable and relatively harmless to metals. Although this constant boiling point mixture contains only 4.4% water, nevertheless ethyl alcohol normally is readily available at moderate price Appropriate mixtures are those con-` and, being used in a closed system, is feasible e heat of vaporization of the secondary butyl alcohol islower than that of ethyl alcohol, nevertheless the increased proportion of water with its very high latent heat of vaporization makes this mixture desirable, especially since it also is a good anti-freeze agent. Where an anti-freeze mixture having a constant boiling temperature in the neighborhood of that of water is required, the previously mentioned di-acetone alcohol mixture may be used because it has an adequately low freezing point and high latent heat of evaporation inasmuch as it contains a high proportion of water (about 87%), although the di-acetone alcohol itself has a very low latent heat of vaporization.

Thus, the three preferred boiling point mixtures described meet all the requirements for motor cooling with evaporative liquids having low freezing points, suitable boiling points, high latent heat of vaporization, chemical stability, and rela-r tive harmlessness to metal.

By employing constant boiling point liquids of this type, reasonably accurate temperature regulation is assured in a sealed, circulating cooling system, the freezing hazard is avoided, liquid pumps are eliminated, and the necessity for frequent liquid replenishment is likewise overcome.

It might be possible to use ethyl alcohol alone, or perhaps methyl alcohol alone, if no objection were found in the loss of benets derived from the high latent heat of vaporization of the water content of the described constant-boiling water mixtures constituting the preferred form of this aspect of the invention.

By employing evaporative liquids in a cooling system, greater cooling eiliciency is accomplished by taking advantage of the high latent heat of vaporization, over that obtained by simply circulating hot liquids, for the reason that a much greater volume of hot liquid is required to produce 'the same amount,of cooling. As a result of employing the present sealed system, a much smaller amount of liquid, and consequent reduction in weight, is possible inasmuch as the vapors are condensed and the condensate returned to the engine. The condenser is always relatively empty of liquid, in view'of the condensation and prompt liquid return, with the result that the entire radiating surface is available for condensation, and with the further result that the amount of radiating surface may be reduced, thereby reducing weight. These conditions are in part a result of the greater efciency of air vcooling to effect condensation of vapor, than to cool liquid contained within a radiator as in the present common water cooling. This is made possible by the fact that a vapor condenser has the same temperature throughout, that is, its temperature is the same from top to bottom, whereas aconventional liquid cooling radiator is relatively cool in its lower portion which therefore dissipates very little heat.

A further advantage resulting from the vaporization of liquid to effect cooling, is the fact that the liquid itself is not circulated, .with the result that in heating up a cold engine the attainment of the desired operating temperature is effected quickly.

A further advantage in the employment of a vin the engine and its temperature 4.4% water; (2) approximately` 72.7%

butyl alcohol by weight and 27.3% water; and

constant boiling mixture in a hermetically sealed system is the ability of the system to care for heat oven-load. Thus, as more heat is developed tends t increase, the increased heat liberated causes the `generation of vapor at a greater rate, and since the condenser will not liquefy the Vapor at the normal boiling point of the liquid, the pressure of the system begins to rise. This rise in pressure increases the boiling point and at the same time it raises the condensation temperature in the condenser. The result is that, for a given temperature of cooling air, the heat is dissipated more rapidly due to the removal of more heat units in a given time at that elevated temperature. Also, the. resultant increase in vapor density inside the condenser expedites heat dissipation, and the net result of all of these factors is that an equilibrium will be established at a l-igher temperature and pressure in the condenser, the heat dissipation at that higher temperature thus equalling the rate of heat absorption without undue rise in engine temperature. Therefore, by proper proportioning of the condenser surfaces with respect to the maximum heat load that the system is intended to handle, any heat load above normal that is encountered in practical operation will be readily cared for.

It is to be understood that other embodiments of this invention may be made in the light of the present teachings, and within the spirit of the condensate to said jacket the entire system being sealed to prevent escape of contained fluids and entrance of extraneous uids.

appended claims, without, however, departing from the broad inventive concept here presented. It is therefore intended that such modifications shall be covered by the claims presented.

I claim as my invention:

l. A method ofcooling internal combustion engines and other engines having cooling liquid jackets comprising: supplying to the jacket by means of a closed. circuit a liquid vaporizable at a predetermined engine temperature, whereby the engine is cooled by vaporization of the liquid; recovering the resultant vapors; condensing said vapors; collecting the resultant condensate; returning the condensate to said jacket; and maintaining the entire circuit sealed, thereby preventing escape of contained fluids and entrance of extraneous uids 2. A method according to claim 1 wherein a head of condensate is established above the level of the engine jacket for gravity feed of liquid to said jacket.

3. A method according to claim 1 wherein said liquid is an anti-freeze mixture having a constant boiling point.

4. A method according to claim 1 wherein said liquid has a constant boiling point and consists of 4one of the liquids of the following class: (1) approximately 95.6% ethyl alcohol by weight and secondary 3) approximately 12.7% di-acetone alcohol by weight and 87.3% water.

5. A cooling system for internal combustion engines and other heat generating engines comprising: a cooling liquid jacket for said engine having a liquid inlet at the bottom and a vapor outlet at the top, there being a vapor space in the upper portion of said jacket;,and a. condenser having a vapor space in the upper portion thereof connected in sealing relation with said outlet of said jacket, said condenser having a liquid space in the lower portion thereof vto receive condensate, said liquid space being connected in sealing relation with the inlet of said `jacket to return 6. A system according to claim 5 wherein the liquid space in said condenser is located at least as high as the liquid level position in said jacket, whereby condensate is fed to said jacketl -`by gravity iiow.

7. In combination: a vehicle having a body; a heat generating engine in said vehicle for Dropelling the vehicle, said engine having a. jacket to receive .cooling liquid, the jacket having an inlet at the bottom and a vapor outlet at the top; a condenser positioned forward of 'said engine, having a vapor space in the upper portion thereof and a liquid receiving space in the lower portion thereof; condenser means located in said body, said condenser means having a vapor receiving space in the upper portion thereof and a condensed liquid receiving space 1n the lower portion thereof; means connecting thevapor receiving spaces of said condensers in sealing relation with the vapor outlet of said jacket; and means connecting the liquid receiving spaces of said condensers with the liquid inlet of said jacket in sealing relation.

9. A combination according to claim 7 and means for selectively bringing said 'condenser means into operative condition for heating the body of said vehicle.

10. A sealed cooling system for heat generating enginesA comprising: a cooling liquid receiving jacket for the engine having a liquid inlet at the lower portion thereof and a vapor outlet at the upper'portion thereof; a condenser means having a vapor space in its upper portion, an intermediate condensing section, and a liquid condensate receiving space in the lower portion; means connecting said vapor space with said vapor outlet in sealing relation; and means connecting said' liquid space with said liquid inlet in sealed relation, said liquid space in said condenser means being positioned with respect to said jacket to feed condensate to said jacket by gravity flow.

1i. A sealed cooling system according to claim 9 wherein the system is .mounted on a vehicle having a body, and said condenser means includes condensing means in said body; and means to place said condensing mean/sfin said body selectively in operative condition for heating said body by reason of the heat absorbed from said condensing means in said body.

12. In combination: an automotive vehicle having a body; an internal combustion engine carried by said vehicle and connected to drive said vehicle; a, cooling liquid receiving jacket for said engine having a liquid inlet at a lower portion thereof anda vapor outlet at an upperl portion thereof; condensing means having a vapor receiving space andv a, condensing section including a condensate receiving space, said condensing means being positioned in said body of said vehicle for heating said body by means of heat absorbed from said condensing means;

means connecting said vapor space with said jacket whereby condensate is fed to said jacket by gravity flow.

14. A combination according to claim 12 wherein said condensing means includes an auxiliary condensing portion located exteriorly of said body and having a vapornspace and a condensate receiving space respectively connected with said vapor outlet and liquid inlet of said jacket.

15. A combination as in claim 12 wherein said jacket includes means providing a vapor re-V ceiving space above a normal liquid level position in said jacket.

16. A method for cooling a heat generating engine having a sealed cooling system including a liquid jacket, condensing means and circulating connections between said jacket and condensing means, comprising; circulating through said system a liquefiable uid which has a constant boiling point and-consists of one ofthe liquids of the following class: (1) approximately 95.6%

ethyl alcohol by weight and 4.4% water; i2) approximately 72.7% secondary butyl alcohol by weight and 27.3% .-water; and (3) approximately 12.7% di-acetone alcohol by Weight and 87.3% water.

17. A method for cooling a heat generatingI engine having a sealed cooling system including a liquid jacket. condensing means and circulating connections between said jacket and condensing means. comprising: circulating through said system a normally liquid anti-free uid mixture containing water and having a. constant boiling point.

I 18. A method according to claiml 17 wherein the constant boiling point mixture employed consists of approximately 72.7% secondary butyl alcohol by weight and 27.3% of water by Weight. i

19. A method according to claim 17 wherein the constant boiling point mixture employed con- I having a liquid inlet at a, lower portion thereof Vand a vapor outlet at an' upper portion thereof;

condensing means having a vapor receiving space and a condensing section including a condensate receiving space, said condensing means being positioned in said body of said vehicle for heating said'body by means of heat absorbed from said condensing means; means connecting said vapor space directly with said vapor outlet; means connecting said condensate receiving spacel of said condensing means directly with said liquid inlet of said jacket; and auxiliary condensing means located exteriorly of said body and having a vaporspace and a condensate receiving space respectively connected directly with said vapor outlet and said liquid inlet of said jacket.

MARION F. KNOY. 

